libppub/src/pprf/Messages/Publish.vala

using Invercargill;
using Invercargill.Convert;

namespace Pprf.Messages {

    public class Publish : AuthenticatedMessage {
    
        public string publication_string { get; set; }
    
        public Publish() {
            message_type = MessageType.PUBLISH;
        }

        public override void authenticate(MemberIdentity identity) {
            member_name = identity.name;
            var checksum = Util.string_checksum(publication_string);
            var auth = new BinaryData.from_byte_array(checksum);
            auth.append(identity.current_state_token);

            authentication = identity.sign_with_individual_signature(auth.to_array());
        }

        public override bool verify(Ppub.Collection collection) {
            var member = collection.members.first_or_default(m => m.name == member_name);
            var auth = Sodium.Asymmetric.Signing.verify(authentication, member.public_keys.signing_key);
            if(auth == null)
                return false;

            var checksum = Util.string_checksum(publication_string);
            var compare = new BinaryData.from_byte_array(checksum);
            compare.append_byte_array(collection.current_state_token);
            
            return compare.equals(ate(auth));
        }
    
        public override void deserialise (GLib.DataInputStream stream) throws Error {
            base.deserialise (stream);

            var data_len = stream.read_uint16();
            if(data_len > 0) {
                publication_string = new BinaryData.from_bytes(stream.read_bytes (data_len)).to_raw_string();
            }
        }
    
        public override uint64 calculate_size() {
            return base.calculate_size() + 
                2 + // Data length
                publication_string.data.length;
        }
        
        public override void serialise(DataOutputStream stream) throws Error {
            base.serialise(stream);

            var data_len = publication_string.data.length;
            stream.put_uint16((uint16)data_len);
            if(data_len > 0) {
                stream.put_string(publication_string);
            }
        }
    }
}